With the recent interest in energy conservation and efficiency, and with the development of solar energy technology, there has been considerable interest in the application of thermal energy storage. Many applications, both industrial and commercial, have been evaluated for possible use of thermal energy storage concepts. The temperature range over which it is desired to store thermal energy varies considerably with these different concepts, and range from approximately 200.degree. F. to temperatures in excess of 1000.degree. F.
Many of the energy storage systems already proposed employ a tape of tank to contain the heated material. However, major design problem are involved with such tanks because of the thermal movements associated with placing the storage tank in service and with the normal temperature cycles through which it operates. These temperature variations cause considerable difficulty in the load bearing insulation and foundation of the storage tank. A need accordingly exists for improved thermal energy storage apparatus.